Powerful computer workstations are dramatically improving biostatistical research and the application of modern biostatistical methods to medical problems. This proposal is an application to obtain a centralized data file server and CPU, a network of satellite workstations, associated peripheral devices, and software to allow investigators to have interactive access to state-of-the-art statistical computing tools and high-resolution graphics. The client/server model of the proposed resource will allow computationally intensive tasks to be undertaken that will enable researchers to fully understand the properties of complex statistical models applied to important clinical problems. Newer interactive data analysis methods supported by the proposed equipment will increase productivity and yield better analyses for a myriad of PHS-supported projects. The system would be a shared resource, serving the needs of many medical divisions and departments. Some of the projects that would be made possible by the proposed network pertain to statistical modeling of patient survival, exact nonparametric tests, Alzheimer's disease, early termination of clinical trials, robust but computer-intensive bootstrap estimation, cancer modeling, effects of treatment timing in coronary disease, DNA and protein sequencing, studies of outcome and treatment variability using large medical databases, studies of . behavioral risk factors, pharmacokinetic modeling, cardiac function, and stochastic models of cardiac arrhythmias. These projects are directly related to car- diovascular disease, critical illness in disabled elderly patients, Sickle cell disease, neurology, cancer, behavioral medicine, and many other areas of medical research. These projects share requirements for expensive resources such as graphics devices, data storage, CPUs capable of intensive computations, and software development and maintenance. The methods that can be developed with this resource will directly benefit research in many important medical problems.